An Analytical Method for Determining Residual Lactide in Polylactide by Gas Chromatography

Area of Science:

• Polymer Chemistry
• Analytical Chemistry

Background:

• Polylactide (PLA) is a biodegradable polymer with increasing applications.
• Accurate quantification of residual lactide monomer is crucial for controlling PLA properties and ensuring product safety.

Purpose of the Study:

• To develop and validate a precise analytical method for determining residual lactide in PLA.
• To establish a reliable quantification strategy using gas chromatography with an internal standard.

Main Methods:

• Gas chromatography (GC) was employed with diphenyl ether (DPE) as an internal standard.
• PLA samples were dissolved, and residual lactide and DPE were extracted into alcohol for GC analysis.
• A numerical analysis method was used to determine the relative response factor, accounting for lactide's reaction with alcohol.

Main Results:

• The developed GC method accurately quantifies residual lactide in PLA.
• The method demonstrated good precision, with a relative standard deviation (RSD) not exceeding 7.0%.

Conclusions:

• The proposed internal standard GC method is suitable for precise residual lactide determination in PLA.
• This analytical approach provides a reliable tool for quality control in PLA production and research.